Fixes #539 -- document which interfaces a backend implements
diff --git a/docs/hazmat/backends/openssl.rst b/docs/hazmat/backends/openssl.rst
index 12d2d9f..4db3972 100644
--- a/docs/hazmat/backends/openssl.rst
+++ b/docs/hazmat/backends/openssl.rst
@@ -7,7 +7,16 @@
.. data:: cryptography.hazmat.backends.openssl.backend
- This is the exposed API for the OpenSSL backend. It has one public attribute.
+ This is the exposed API for the OpenSSL backend.
+
+ It implements the following interfaces:
+
+ * :class:`~cryptography.hazmat.backends.interfaces.CipherBackend`
+ * :class:`~cryptography.hazmat.backends.interfaces.HashBackend`
+ * :class:`~cryptography.hazmat.backends.interfaces.HMACBackend`
+ * :class:`~cryptography.hazmat.backends.interfaces.PBKDF2HMACBackend`
+
+ It has one additional public attribute.
.. attribute:: name